The present invention concerns in general improved receptacle dumping apparatus and in particular concerns lifter technology with universally adaptive features for use with residential refuse collection carts of different types, and other lifter and nonlifter improvements.
Technology related to residential refuse collection (and other service areas) has advanced in the last several decades generally from the use of metal trash cans which were manually lifted and dumped to the use of receptacles with wheels which are rolled by the resident down a driveway or the like to a curb location at which the receptacle is lifted and dumped by a particular lifting apparatus. One example of such a lifting apparatus for lifting and dumping rollable receptacles is disclosed in Bayne et al. (U.S. Pat. No. 4,773,812) issued Sep. 27, 1988, and Reexamination Certificate issued on Apr. 16, 1991.
As the number of designers competing in the newer technology rolling carts and cart lifters increased, different styles of carts emerged together with specialized lifters for handling a specific cart type.
One cart type which became prominent includes two opposing engagement members located respectively near the top and middle of the cart and which are grasped for lifting and dumping of the cart. Operation of a lifting element below the upper cart engagement member permits the cart to be lifted while operation of another engaging element in the opposite direction and directed at the lower cart engagement member permits the cart to be retained on a carriage as the cart is raised and inverted during dumping. Such cart style is in the industry sometimes referred to as a bar lift cart or U.S. or "Domestic" style cart.
The following patents all provide examples of such domestic cart style and typically hydraulically actuated lifting devices for raising and inverting such carts for dumping the contents thereof into a further receptacle such as a refuse collection vehicle or a relatively larger collection box. See for example the cart 10 of FIG. 7 of Shive (U.S. Pat. No. 3,894,642), as well as the carts and corresponding lifters therefor as utilized in Borders (U.S. Pat. Nos. 4,422,814 and 4,365,922), and Brown et al. (U.S. Pat. No. 3,804,277). In general, such patents disclose various mechanisms for controllably manipulating a lower engagement member of the lifter in a generally downward direction for engaging the relative top side of a lower engagement bar of the cart to be emptied. Each of the patents are commonly assigned to Rubbermaid Corporation of Statesville, N.C., or its successor Applied Products, Inc., of Statesville, N.C., now Toter, Inc., of Statesville, N.C., a manufacturer or distributor of roll-out carts and cart lifters.
An alternate version of the "Domestic" style cart is represented by refuse container 12 of FIG. 1 of Wyman et al,. (U.S. Pat. No. 4,479,751). In such patent, the receptacle itself has two separate bars which are again engaged by respective upper and lower lifter engagement members. The lower lifter engagement member is again pivoted in a relatively downward direction for engaging the relatively upper most surface of the lower cart bar. A second bar is substituted in the upper position in place of the molded engagement region or moldably encased bar of the above-referenced Toter, Inc., patent designs.
Other examples of lifter mechanisms designed for use with specific (and rollable) refuse containers are disclosed by Jones (U.S. Pat. No. 3,931,901) and Wells (U.S. Pat. No. 3,738,516).
Another style of roll-out cart which has become relatively prominent is known as a "European" style cart. Such a cart has generally smooth sides (i.e., does not have external bars or their equivalents along a side thereof, but has instead a molded upper lip which is adequately reinforced and sized for being adequately clamped for lifting and dumping of the "European" style cart by engagement at such single engagement member or point. An example of such a "European" style cart is represented by cart 50 of FIG. 3 of Naab (U.S. Pat. No. 4,613,271).
Generally speaking, the same lifter mechanism features (i.e., engagement members) cannot be used for engaging and lifting different cart styles, particularly as between the above-described "Domestic" and "European" cart styles and related variations. Therefore, most cart lifters have heretofore been of a dedicated design, that is, structured for use with either the European style cart or the domestic style cart, but not both. At the same time, the increase of companies competing for residential trash pickup in a single neighborhood, and due to other factors, has resulted in mixed varieties or styles of carts on a single trash pickup route. Such situation necessitates that the refuse collection vehicle be somehow equipped for handling (i.e., lifting and dumping) the different cart styles which will likely be encounted during a typical trash collection run.
While refuse collection vehicle styles have varied in recent years, just as has the technology described above (such as rear load, side load, and front load vehicles), only several lifter units can be ordinarily outfitted onto a refuse collection vehicle at a given time. Therefore, an entire truck or refuse collection vehicle becomes in a sense dedicated to a particular cart style just as does the design of the lifter. Since refuse collection vehicles can cost as much as One Hundred Fifty Thousand Dollars ($150,000), requiring duplication of vehicles simply in order to handle different cart styles which may be encountered can be a very expensive approach to a widespread problem.
The above-referenced U.S. Pat. No. 4,613,271 to Naab seeks to address one aspect of such problems by providing a device which is capable of emptying different style garbage containers. Such arrangement involves providing on a single unit both a clamping mechanism for grasping a molded upper lip of European style carts and opposing engagement members for engaging paired lift engagement members of a domestic style cart. See cart 50 of FIG. 3 and cart 55 of FIG. 4, respectively, of the Naab patent. Naab uses a gravity or spring system in conjunction with an upper gripper 37 to permit the gripper to be pivoted out of the way for operation of a clamp mechanism whenever a European style cart is presented. At the same time, Naab provides a lower cart engagement member which is pivoted generally in the same direction as the above-described prior art arrangements for lifting domestic style carts. In other words, the lower engagement member of Naab is pivoted upwardly into a retracted position during dumping of European style carts, but pivoted downwardly into an extended position against the relatively uppermost side of the lower lift engagement member of a cart whenever a domestic style cart is being dumped.
The Naab arrangement utilizes a spring 45 for biasing a locking hook 44 into an upwardly pivoted or retracted position. Naab then uses various arrangements for overcoming such biasing and positively moving locking hook 44 outward and downward into engagement with a lower lift bar whenever a domestic style cart is being dumped.
In some embodiments, Naab uses a specific turn-on/turnoff device keyed by a switch actuator 67 which itself is actuated by contact from gripper 37. Electric, hydraulic valve, or mechanical means may be associated with such switch actuator 67 for changing the position of an adjustable settable sleeve. Naab FIG. 8 illustrates an electromagnetic switchable version while Naab FIG. 9 illustrates a fluid power (e.g., hydraulic) arrangement.
In some embodiments, such as that shown in FIGS. 12 through 15, Naab uses a counterlocking device for placement of the locking hook depending on the movement of other members (for example, gravity arm 87) during operation of the lift.
With respect to relative size considerations, the thickness of the overall Naab lift (i.e., the distance between where it is supported and the point at which a cart is engaged to be picked up) must necessarily accommodate the different mechanisms by which the Naab device functions in order to advance locking hook 44 outward and downward towards a lower lift bar. Such arrangement therefore serves as one limitation to minimizing such lifter thickness.
Another aspect of Naab is that the top clamp 35 of Naab for clamping European style carts is in a relatively fixed position and the cart molded lip is brought into contact with the lower side of element 35, as a carrying element 33 is positively moved upward from beneath the cart lip. Such an arrangement encompasses a certain minimum required mechanical operations, which again necessitates a certain thickness for the Naab lifter.
In addition to the strong need and desire for an efficient lifter which has universal features for lifting carts of different styles (i.e., domestic or European style carts), it is also a fact that carts of different sizes, and hence often times of different heights, are encountered on a residential refuse collection run, not to mention the variety encountered in other settings. The need arises to match the physical characteristics of a lifter with the size of the container to be dumped. If the initial engagement feature of the lifter is below the uppermost engagement feature of the cart, potentially dangerous operations can ensue since the lifter might be actuated into a partially raised and/or partially inverted position before the cart is properly or fully (i.e., safely) engaged. On the other hand, if the uppermost engagement feature of the lifter is above the uppermost engagement feature of the cart, then the cart must somehow be lifted upwardly until engagement is made, which may be literally impossible to do manually whenever carts have loads therein upwards of 200 pounds. At the very least, repeated such manual operations can give rise to physical stresses and injuries of operators.
In addition to the foregoing, it is desirable to have smooth, stable operations during a dumping cycle. Instability can come about for a variety of reasons. For example, a load of 200 pounds on the end of extended arms can exert tremendous torque forces if the load is not balanced. Hence, any lateral looseness in a lift system could be an area of concern for a long term maintenance problem.
Also, the speed and smoothness of lift operations are important. For example a jerking (i.e., non-smooth) motion of a 200 pound weight on the end of extended arms can create maintenance problems (and even arm breakage) over time. Potentially adverse consequences of jerking can peak whenever the lift arms are most extended, i.e. whenever the cart is fully raised and inverted for dumping the contents thereof. Motion dampening at such moment could serve to limit or reduce wear and strain on both the cart and the lifter.
The entire disclosures of the U.S. patents noted above are herewith incorporated by reference into the subject disclosure.